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AP® Physics C: E & M

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Moderate

Inside-Outside Field

APPHEM-EVYDHO

The diagram shows a charged sphere $+Q$ in the center of a conducting spherical shell. Electric field lines are drawn in the region between the sphere and the shell and also in the region outside the shell.

A student observing the diagram decides that the shell carries a net charge of $-Q$ since there are the same number of lines outside the shell as inside, and because the lines outside point radially inward. Is the student correct?

A

Yes, because the same number of lines indicates the same amount of charge.

B

Yes, because the electric field outside the shell only depends on the charge of the shell.

C

No, the charge on the shell has a magnitude that is less than $|Q|$.

D

No, the charge on the shell has a magnitude that is greater than $|Q|$.

E

No, the charge on the shell is positive, not negative.